Searchlight for exploring the sky



p 1934- M. FERRERO tr AL SEARCHLIGHT FOR EXPLORING THE SKY I Fi-led Nov. 12, 1932 2 Sheets-Sheet l MARIO FERRERO ETTORE. SALANM 2: BY

mvsmoRs w H ATTORNEYS Sept. 11, 1934. M. FERRERO ET AL SEARCHLIGHT FOR EXPLORI NGTHE #KY 2 Sheets-Shet 2 1 Filed NOV. 12, 1932 MARIO FERRERO ,"ETT'ORE. SALANI YINVENTORS BY MC, ATTORNEYS Patented Sept. 11, 1934 UNITED STATES PATENT oFFIcE-f Mario Ferrero and Ettore Salani, Rome, Italy Application November 12, 1932, Serial No. 642,374 In Italy November 19, 1931 2 Claims. (01. 240-12) The present invention refers to the construcand to exactly reproduce the shape of the support, tion of a Searchlight primarily intended for the on which they are pp Said Supports havin exploration of the sky by illuminating successively been previously cut or bent to the desired shape, all parts of the same so as to facilitate the task with the result that the metal sheets appli d I of discovering and following the position of any thereon. 1 fi y disposed i o da e w t 60 aircraft which may happen to be travelling within the proper form of. the reflecting surface. It will reach of its beam of light. be apparent that by mounting several sheets of With this object in view the reflecting surface metal side by side so that one adjoins the other,. of the searchiight. according to the present ineach sheet being one or two meters wide, it will 10' vention,- insteadof including the usual form of a be possible to build reflectors of any size desired. 05

surface of revolution, has the form of a parabolic The annexed drawings show schematically by cylinder, so that when the reflector is placed with way of example the construction of a parabolicits focal line in a horizontal direction, it produces cy i drical mi or accord to he. invention, in a fan shaped beam of light passing through the which l5 zenith of the place and extending downward to 1 shows the cross section through the 70, two diametrically opposite points of the horizon. searchlight, in a plane perpendicular to the gen- When such a searchlight is rotatably mounted on eratrix of the cylinder.

a central vertical pivot, the searchlight during its Fig. 2 shows the searchlight in front elevation. rotation will illuminate successively all the parts Fig. 3 shows the Searchlight mounted on a reof the sky, thus rendering it quite easy to detect volving truck, capable of rotating round its cen- 75 the presence of any aircraft, and to follow its tral vertical axis. course, particularly if it travels in one of the As showninthe drawings, the searchlight comvertical planes passing through the place of prises a series of supporting plates or girders 1 observation, because in such case it will remain (having a parabolic. profile in the case under .25 continually within the beam of light without consideration) whichare mounted parallel with moving the searchlight, which would never be respect to each other, against the surface of which possible with reflectors having the form of a one or more rectangular sheets 2 are appliedby surface of revolution. v bending the same, the concave part of which is While it has already been proposed to apply polished and covered by electrolytic deposition 30' sheet glass in molded parabolic supports, yet the of a metal so as to obtain a mirror surface (silver, 5 very limited range of elasticity of glass prevents gold, nickel, chromium etc). The edges of the 1 the same from being applied in extensive sheets sheet penetrate into the concave part of two U which would cover more than a very small portion shaped irons 3', 3", which serve as continuous of such supports, and also only utilize a small abutments, for obtaining the pressure equally disportion of the light from the source thereof. tributed, and one of which, 3", is adjustable by 90 While it has also been proposed to apply strips or means of the screws 4 passing through the supfoils to molded templets, it is now proposed herein ports 15, or by any other convenient means, so as to provide means for retaining said strips or foils tomake certain that the sheet 2, when inflected, in position thereon and also for compensating for may be laid precisely on the supports. The said 40 the expansion and contraction of the strips resupports are constructed in such manner as to 5 sulting from the effects of heat. allow the movements of the flexible sheet due to It is to be remarked, however, that, in order' to thermal action. illuminate at one time a strip of the sky extend- Moreover, in order to diminish or to annul the ing thus between two opposite points of the horisaid movements, it is convenient to use, for the 4M5v zon, the searchlight of the usual size would be construction of the supports and of the metal 100 altogether inadequate. On the other hand it sheets, materials having approximately the same woul b a y, fl in fa an imcoefllclent of thermal dilation or expansion. possible task to buildglass reflectors of the size A series of ordinary lamps 5 carried by a suprequired, for instance covering about 40 to port 6, or a single tubular lamp disposed along the 50 square meters of surface. focal line of the reflector, constitute the source 195 According to the present invention, said probof light. lem is solved in a simple way by taking advan- Fig. 3 shows th searehlight mounted on a retage, in the construction of the mirrors, of the volving truck 8 carried by the peripherical wheels -elasticity of thin. metal sheets which allow of 7 running round a central vertical pivot 16, on

their bending, thus causing them to adhere to a suitable flat platform 9. .By rotating the said no truck, the Searchlight will illuminate successively all the parts of the sky, and it will thus be easy to discover and to follow the position of any aircraft travelling within reach of its beam 01' light.

We claim: l. A cylindrical parabolic reflector for seachlights adapted to project a narrow beam of light passing through the zenith above said reflector and extending between two opposite points 01' the horizon, including the combination of a support which is rotatable in a horizontal plane about a pivot having a vertical axis, a plurality of parallel spaced templets rigidly secured upon said support and having corresponding concave interior profiles, and flexible reflecting polished sheet metal bent and fitted to and resting on the interior profile edges so as to connect all of said templets and form a concave horizontal cylindrical reflecting member which is open along the top and a plurality of lights disposed in a horizontal row within said reflecting member.

2. A searchlight reflector according to claim 1,

I wherein the flexible polished sheet metal which is fitted against the interior profile edges of the templets in order to conform to the concave shape thereof, has the upper edges fitted against abut- 

